#define   _CRT_SECURE_NO_WARNINGS  1
#pragma warning(disable:6031)
#include<stdio.h>
#include<string.h>
#include<stdlib.h>
#include<math.h>
#if 0
#define swap(x) ((x&0xAAAAAAAA)>>1)|((x&0x55555555)<<1)
int main()
{
    int x = 54;
    printf("%d\n", x);
    x = swap(x);
    printf("%d\n", x);
     return 0;
}
#endif
#include <stddef.h>
//#define offsetof(type,number) ((size_t)(&((type*)0)->number))
struct U {
    char a;
    int name[20];
    long age;
};
int main()
{
    size_t x = offsetof(struct U, name[1]);
    printf("%zd\n", x);
    return 0;
}